No-Nonsense Flutter Apps for Beginners

Flutter is an open-source framework that allows developers to create high-performance, aesthetically pleasing, and feature-rich mobile applications for both Android and iOS platforms. The framework uses the Dart programming language, and was created by Google in 2017. Due to its efficiency, ease of use, and ability to create cross-platform apps with a single codebase, it’s become increasingly popular among developers in the past years.

Flutters main advantage is its reactive programming model, which enables quick and fluid user interfaces. This makes it easier to develop responsive and interactive apps by rebuilding and updating widgets whenever data changes. Additionally, Flutter’s widget-based architecture allows for building customizable and dynamic user interfaces.

In this comprehensive guide, you’ll be learning the ins and outs of the Flutter framework. We’ll go over creating an app from scratch, and cover everything from setting up the development environment, to finally publishing your app on your app store of choice.

Without any further to do, let’s get right into it.

Getting Started

To start developing with Flutter, you’ll need to have Flutter SDK installed on your computer, which is the bundle that includes everything you need to develop Flutter applications. You can download the SDK from the official Flutter website.

Once downloaded, add it to your PATH. This will enable you to use the Flutter CLI (Command Line Interface) to create new projects and run the starter app.

Then, extract the downloaded Flutter SDK to a location on your computer. When done, open the terminal or command prompt and enter the following command:

export PATH="$PATH:pwd/flutter/bin"

You can check to see if Flutter is correctly installed by running the following command:

flutter doctor

Flutter is also compatible with a variety of code editors, including Android Studio and Visual Studio Code. To set up either of these code editors for Flutter development, start with downloading your code editor of choice, then begin to install the Flutter and Dart plugins for your chosen code editor. Finally, configure the SDK path for Flutter and Dart in the settings.

Creating a Project

To create a new project, start with opening your terminal or command prompt, and navigate to the directory where you want to create your project.

Enter the following command to create a new Flutter project:

flutter create <project_name>

Wait for the CLI to finish creating the project. Once the project is created, you should see a directory with the same name as your project containing the starter app files.

Flutter starter app provides a basic project structure that you can use as a starting point for your application. Here’s a brief overview of the files and directories included in the starter app:

• lib/: This directory contains the main Dart code for your application.

• android/: This directory contains the Android-specific files for your application.

• ios: This directory contains the iOS-specific files for your application.

• test/: This directory contains the unit and widget tests for your application.

• pubspec.yaml: This file is used to define the dependencies and metadata for your application.

To run the starter app, begin by connecting your Android or iOS device to your computer. Alternatively, you can also choose start an emulator. Open your terminal or command prompt and navigate to the root directory of your project, then enter the "flutter run" command to compile and run the app on the connected device or emulator.

Understanding Widgets

Widgets are the building blocks of a Flutter application, and they’re used to create the user interface of your application. Widgets are essentially visual components that can be combined and nested to create complex and dynamic user interfaces.

Flutter provides a vast library of widgets that you can use to create your application, ranging from basic widgets like Text and Container to more advanced widgets like ListView and GridView. You can also create your own custom widgets to suit your application’s needs.

Here’s an overview of some of the most common types of widgets:

• Stateless Widgets: These widgets are immutable and do not change over time. They are used to create static UI elements like text, images, or buttons.

• Stateful Widgets: These widgets have mutable state, and their appearance can change over time. They are used to create dynamic UI elements like forms, animations, or charts.

• Layout Widgets: These widgets are used to arrange other widgets in a specific layout, such as rows, columns, or grids.

• Material Widgets: These widgets implement the Material Design guidelines and are used to create UI elements that look and feel like a native Android app.

• Cupertino Widgets: These widgets implement the Cupertino Design guidelines and are used to create UI elements that look and feel like a native iOS app.

To create a basic widget, start by opening the main.dart file in the lib directory of your project. Delete the existing code in the file and add the following code to create a Text widget:

import 'package:flutter/material.dart'; void main() => runApp(MyApp());

class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'My First Flutter App', home: Scaffold( appBar: AppBar( title: Text('My First FlutterApp'), ), body: Center( child: Text('Hello, World!'), ), ), ); } }

This code creates a Text widget with the text “Hello, World!” centered on the screen. The Scaffold widget provides the basic structure of the app, including the AppBar and the body where you can place your widgets.

To run the widget, follow the same steps as before:

Connect your Android or iOS device to your computer. Alternatively, you can also choose start an emulator. Open your terminal or command prompt and navigate to the root directory of your project, then enter the "flutter run" command to compile and run the app on the connected device or emulator.

Designing a UI

Flutter provides a powerful and flexible framework for designing user interfaces. With its rich library of widgets and tools, you can create beautiful and engaging UIs that can run on both Android and iOS devices. In this section, we will explore some of the key concepts and tools you can use to design UIs in Flutter.

Understanding Layout Widgets

Layout widgets are used to arrange other widgets in a specific layout. Flutter provides a variety of layout widgets that you can use to create different types of UIs. Some of the most common layout widgets include:

• Container: A widget that can contain other widgets and can be customized with properties like padding, margin, and background color.

• Row and Column: Widgets that arrange their child widgets in a horizontal or vertical row, respectively.

• Stack: A widget that allows you to stack child widgets on top of each other.

• Expanded: A widget that expands to fill the available space in its parent widget.

Customizing the UI with themes

Themes allow you to apply a consistent look and feel across your application. In Flutter, you can customize the theme using the Theme widget. The Theme widget takes a ThemeData object, which contains properties like primaryColor, accentColor, and textTheme that can be customized to create a unique look for your application.

Using Flutter widgets for common UI components

Flutter provides a vast library of widgets that can be used to create common UI components like buttons, text inputs, and images. Here are some examples of common widgets:

• Text: A widget that displays a text string.

• TextField: A widget that allows users to enter text.

• Image: A widget that displays an image.

• RaisedButton: A widget that displays a button with a raised appearance.

• FlatButton: A widget that displays a button with a flat appearance.

Creating custom widgets

In addition to the built-in widgets provided by Flutter, you can also create your own custom widgets, which will allow you to encapsulate complex UI elements and reuse them throughout your application. To create a custom widget, simply create a new class that extends StatelessWidget or StatefulWidget and override the build method to return the UI of the widget.

Managing State

State refers to the data that changes over time in your application. For example, the data entered by a user in a text field, the number of items in a shopping cart, or the current location of the user. In Flutter, there are two types of state: Ephemeral and App State.

• Ephemeral State: This is the state that is local to a single widget and does not need to be shared with other widgets. For example, the current value entered by a user in a text field.

• App State: This is the state that needs to be shared across multiple widgets in the application. For example, the user’s authentication status, the current theme of the app, or the data fetched from an API.

Flutter provides several options for managing state in your application:

• setState(): This is the most basic way to manage state in Flutter. When a widget’s state changes, you can call the setState() method to update the UI of the widget. However, this approach can become cumbersome when dealing with complex UIs or state that needs to be shared across multiple widgets.

• InheritedWidget: This is a widget that allows you to share state across multiple widgets in your app. It works by passing down a piece of data from a parent widget to its children. This approach is useful when you need to share app-wide state that can be modified by multiple widgets.

• Provider package: This is a package that simplifies state management in Flutter. It provides a convenient way to share app-wide state across multiple widgets. It uses the InheritedWidget approach under the hood but provides a more elegant API for working with state.

• BLoC pattern: This is an architecture pattern that separates the business logic of an application from its UI. It involves creating a separate class for managing the state of the app and using streams to communicate changes in the state to the UI. This approach can be more complex but provides a clear separation of concerns and can make it easier to test your app.

When it comes to managing state in your Flutter app, there is no one-size-fits-all solution. The approach you choose will depend on the complexity of your UI, the size of your app, and the nature of the state you need to manage. In general, you should aim for an approach that is simple, easy to understand, and maintainable.

Testing and Debugging

Flutter provides a powerful testing framework that makes it easy to write and run automated tests for your app. You can use the framework to write unit tests, widget tests, and integration tests.

• Unit Tests: These tests are used to test individual functions, methods, or classes of your app. They are lightweight and fast, making them ideal for testing small, isolated pieces of code. Flutter provides a test package that you can use to write and run unit tests for your app.

• Widget Tests: These tests are used to test the UI components of your app, such as buttons, forms, and layouts. They simulate user interactions with the app and ensure that the widgets behave as expected. Flutter provides a flutter_test package that you can use to write and run widget tests for your app.

• Integration Tests: These tests are used to test the interaction between different parts of your app, such as data storage, networking, and UI components. They are more complex and time-consuming than unit and widget tests but are essential for testing the app as a whole. Flutter provides a flutter_driver package that you can use to write and run integration tests for your app.

Flutter provides several tools and techniques that make it easier for you to fix errors and debug your app, including the following:

• Logging: Logging is a way to output information about your app to the console. You can use the print function to output information to the console, or you can use the dart:developer library to log more detailed information.

• Debugging Tools: Flutter provides several debugging tools, including the DevTools web app, which allows you to inspect and debug your app in real-time. You can use DevTools to inspect the widget tree, view logs, and track performance metrics.

• Hot Reload: Hot Reload is a feature that allows you to quickly make changes to your app and see the changes in real-time without having to restart the app. This feature can save you a lot of time when debugging your app.

Publishing your App

Google Play Store

1. Create a release: In the Flutter project, run flutter build apk — release to build an APK file of your app.

2. Create a Google Play Console account: Go to the Google Play Console website, sign in with your Google account, and create a new app.

3. Upload your APK file: In the Google Play Console, go to the “Release” section, and upload the APK file that you created in step 1.

4. Fill in the app details: In the Google Play Console, fill in the app details, such as the app name, description, and screenshots.

5. Set the app pricing and availability: In the Google Play Console, set the app pricing and availability for different regions.

6. Submit the app for review: In the Google Play Console, submit the app for review. The review process can take a few days, and the app may be rejected if it does not meet the guidelines of the Google Play Store.

Apple App Store

1. Create a release: In the Flutter project, run flutter build ios — release to build an IPA file of your app.

2. Create an Apple Developer account: Go to the Apple Developer website, sign in with your Apple ID, and create a new app.

3. Upload your IPA file: In the Apple Developer website, go to the “App Store Connect” section, and upload the IPA file that you created in step 1.

4. Fill in the app details: In the App Store Connect, fill in the app details, such as the app name, description, and screenshots.

5. Set the app pricing and availability: In the App Store Connect, set the app pricing and availability for different regions.

6. Submit the app for review: In the App Store Connect, submit the app for review. The review process can take a few days, and the app may be rejected if it does not meet the guidelines of the Apple App Store.

Mobile applications have become an essential part of our lives, and the demand for them is constantly increasing. With the rise of smartphones and mobile devices, businesses need to have a mobile presence to stay relevant and competitive, and having the knowledge of frameworks like Flutter are great for this demand in the field.

I hope that this guide has provided you with a solid foundation for developing your own Flutter app. The journey of development can certainly be challenging, but with the right approach, it can also be very rewarding in the end. As you progress, you’ll continually discover new features and techniques that can enhance your app’s functionality and user experience.

Test new things, have fun, and don’t stress. In the meantime, be on the lookout for more of my upcoming articles, and I’ll see all of you very soon.